Will Hard Drives be Powered by Sound?

According to Forbes, four years ago the total mount of digital information in the world came out to about 2.7 zettabytes. For those of you unfamiliar with imperceptibly large numbers, that’s 2.7 x 10^21 bytes. That means in 2012, there were a few trillion bytes for every one of the 7 billion people on earth. Given that the amount of digital information in the world tends to double every year and a half, tech experts have predicted that we’ll generate around 40 zettabytes by 2020.

That’s a lot of information to store physically, whether you’re using hard disk drives that encode data magnetically or solid-state drives that store data using the presence and absence of tiny electrical charges. Each storage method has its downfalls; hard drives are limited in terms of how small they can be due to the spinning disks integral to their engineering. Solid-state drives can be made smaller due to their lack of mechanical parts, but their lifespan tends to be shorter and they’re much more expensive.

Engineers at IBM have figured out that the best storage drive would be a marriage of the two existing options: a solid-state drive that encodes data magnetically. IMB’s prototype uses something called racetrack memory, which is comprised of collections of nanowire. These wires are hundreds of times thinner than a human hair, yet they’re large enough to hold magnetically encoded binary information. The task of reading and writing information is performed by sensors, but finding the exact method for how the data will pass between the wire and sensors has proven to be a bit of a challenge. The old stand-by of using magnetic fields or electric currents to relay data still works, but these older methods come with a host of other problems like heat generation, reduced power efficiency, and affected battery life.

Tom Hayward, a researcher at the University of Sheffield, informed The Conversation of how he found a way to make racetrack memory more efficient. Hayward was working with his group in conjunction with John Cunningham at the University of Leeds when they realized that there was a surprising potential solution.

According to Hayward’s teams’ findings, which are now published in Applied Physics Letters, they were able to set up simulations in which vibration-sensitive magnetic nanowires were set on top of piezoelectric materials that stretched when electric voltage was applied to them.

Piezoelectricity is electricity that occurs when mechanical stress is applied to an object.

When Hayward’s team applied a rapidly-switching voltage to the piezoelectric materials, they began to vibrate and create a very particular kind of sound wave known as a surface acoustic wave. The team used this method to create two different kinds of surface acoustic waves; one which flowed forwards and one which flowed backwards.

The way that these sound waves interact with the nanowire allows for data to be, in a sense, pushed and pulled along the nanowire at a rate of 100 mph. Hayward’s team believes that this speed can be increased by a factor of ten upon further research. They’ve yet to produce a working prototype, but it’s safe to say that data storage will never be the same if they do.